session-format-v0-to-v1 converter refuses loadable v0 sessions over cosmetic fields (history load breaks after upgrade to 0.1.5-rc.1)

[rui08984-dot]

Environment

• Upgrade path: @deepseek-ai/dsh 0.1.2-rc.1 → 0.1.5-rc.1 (web profile)
• OS: Windows 11, Node 24.18
• Real production sessions (weeks of multi-agent work, 40+ subagents each)

Symptom

After upgrading, opening any pre-upgrade session fails to load history:

failed to observe session "session-...": @deepseek-ai/dsh-session-format-v0-to-v1
refuses this format v0 Session: user/message 22 source summary requires notice form
(source v0 artifact remains unchanged)

The raw v0 artifact is untouched — the user simply loses all in-UI access to weeks of work after upgrading.

Two distinct refusal triggers found (real sessions, both reproduced)

1. user/message notice source carries summary but form != "notice"
   → throws summary requires notice form.
   The summary is display metadata only; the session content does not depend on it.
2. permission/preset data carries an extra origin key
   → throws has unexpected member "origin" (the released-v0-keys table for permission/preset admits only preset).

Why this hurts

A read-path converter failing closed on cosmetic/display fields means every 0.1.2-era session becomes inaccessible after a routine upgrade. In our case two main working sessions (430K+ tokens, 40+ subagents of history) were blocked.

Suggestion

Tolerate-and-coerce on the read path instead of refusing:

• stray summary on a non-notice form → drop the field (metadata only)
• permission/preset data → admit origin as an optional key

Local workaround confirmed

Coercing both cases (delete stray summary / admit optional origin) restores full history load on 0.1.5-rc.1 — verified against real affected sessions.

[xiaoshenming]

Covered as well (v0-plugin-source-form): when form is absent, repair adds the matching literal — notice for a summary, snapshot for sections — and keeps the metadata; when form conflicts, only the display-only member is dropped. Message body text is never touched.

Verified against the released 0.1.5-rc.1 sessionFormatV0ToV1 stage (refused before, clean after). Note the same refusal also fires for sections without form: "snapshot". Repair only rewrites when the installed runtime migrates v0 itself; details in #6151.

[michaelSun07]

+1, hit the same after upgrading to 0.1.5-rc.1. Traced it to
dsh-session-format-v0-to-v1/lib/index.js — in pluginSourceValue this line:

else if (source["summary"] !== void 0)
    throw new SessionFormatError(${label} summary requires notice form);

rejects any v0 plugin source whose form isn't "notice" but still carries a
summary. Those v0 records loaded fine on 0.1.2; the migration should
tolerate (or normalize) the legacy combination instead of refusing the whole
session. A local workaround is to drop that one throw, but it's overwritten
on the next dsh update.

[xiaoshenming]

@michaelSun07 你定位到的 summary requires notice form 正是同一处。修复已改成对齐 form 而不是删成员：只有 summary 时把 form 补/改成 notice（summary 保留），只有 sections 时对齐 snapshot；两者并存才丢弃冲突的那个。正文不动，--apply 先写 .bak.。装最新 #main 即可，详见 #6151 里 09-10 的说明。